Vibrating and other separatory screen assemblies are generally known in the art and are very useful in accomplishing the separation of materials, on the basis of the size of the materials to be separated. A slurry of liquid and entrained solids can be caused to run or to flow across an upper surface of a screen panel assembly. Particles of at least a certain size will not pass through apertures in the screen panels and will thus be separated out of the slurry. The screen panel assembly is caused to vibrate by a suitable vibratory drive, with this vibratory motion being beneficial in facilitating the proper separation of the slurry which is directed onto the screen panel.
One such vibrating separatory screen panel assembly is shown in U.S. Pat. Nos. 5,112,475 and 5,277,319, both to Henry, and both assigned to Conn-Weld Industries, the assignee of the present application. In those two patents, there is disclosed a screen panel mounting system for a vibrating screen assembly. There is also disclosed a screen panel which is securable in the vibrating screen assembly by using the panel mounting system. A plurality of screen panels are secured to a panel deck of a frame portion of a vibrating screen assembly. A plurality of elongated hold downs or center retainers, which are made of a resilient elastomeric material, such as polyurethane, are provided with integral spaced anchoring pins along their bottom surface. Those integral, spaced anchoring pins are receivable in apertures in an anchor member. Once the hold down members or center retainers have been secured to the anchor member, which is, in turn, attached to spaced cross members or tubes of the frame of the vibratory separator, the screen panels are placed atop the panel deck with their side edges in contact with the center retainers. Elongated key members are inserted into upwardly facing slots in the center retainers to spread wing portions of the retainers laterally outwardly. This spreading of the wings of the center retainers causes the wings to grip the side edges of the screen panels so that these panels are secured in the vibrating screen assembly.
A center retainer assembly for a panel mounting system is disclosed in U.S. Pat. No. 5,398,817 to Connolly et al. which is also assigned to Conn-Weld Industries. The center retainer assembly described in the '817 patent utilizes an elongated bolting bar which is encased in a resilient material and which includes an elongated center retainer. The center retainer assembly of this patent is placed into an upwardly facing retainer channel and is secured to the retainer channel by placement of the bolts carried by the bolting bar through holes in the retainer channel. The retainer channel is, in turn, secured to mounting plates that are attached to a cross tube or to a cross bar of a vibrating screen assembly.
A more recent screen panel retainer system is described in U.S. Pat. No. 6,964,341 to Bacho et al. That patent is also assigned to Conn-Weld Industries, the assignee of the subject patent application. In that system, the screen panels are held in place by screen panel edge strips which have pockets on their undersurfaces. Those pockets are cooperatively shaped to receive a plurality of ears that are situated on upper surfaces of retainer bars. Those retainer bars are connected to the underlying deck stringer tubes.
A snap lock separatory panel and retainer system is disclosed in U.S. Pat. No. 7,717,269, also to Bacho et al., and also assigned to Conn-Weld Industries, Inc. In that patent there is disclosed a snap lock separatory panel retainer system as well as a separatory panel which is usable with the retainer system. Elongated locking strips are used to engage locking profiles on the separatory screen panels. Those locking strips utilize undercut receptacles to receive enlarged heads of retainer pins that are formed integrally with center retainer strips. Those center retainer strips are, in turn, secured to the deck stringer tubes that are typically provided in vibrating separatory machines. The locking strips are snap locked onto the center retainer by the engagement of the enlarged heads of the retainer pins in the cooperatively shaped undercut receptacles in the locking strips.
Another screen panel retainer system is described and depicted in U.S. patent application Ser. No. 13/049,000 which was filed on Mar. 16, 2011 in the names of inventors James D. Connolly et al, which issued as U.S. Pat. No. 8,281,934 on Oct. 9, 2012 and which is also assigned to CONN-WELD INDUSTRIES, INC. This patent describes a screen panel retainer system in which a plurality of metal retainer bars are attachable to the underlying surface of the vibrating separatory device machine frame. Each such metal retainer bar is provided with spaced, upwardly projecting, generally mushroom-shaped screen panel retainers. The retainers are rigid and are shaped to be receivable in cooperatively shaped retainer receiving chambers in either urethane screen panel edges or profile wire screen panel edges.
The various screen panel retainer systems, as described and depicted in the several Conn-Weld Industries patents and applications discussed above, have all enjoyed some degree of success in the industry. However, each has its individual limitations which have made each system less than suitable for use in all equipment, regardless of manufacturer and configuration. Several of the earlier systems required modification or reworking of the industry standard deck stringer tubes. Others, such as the system described in the Bacho et al. U.S. Pat. No. 6,964,341 have been found somewhat difficult to use and have required the provision of screen panel edge strips that have had to be field-installed on the replacement screen panels. Adjacent screen panels have sometimes required the use of cooperating and abutting screen panel edge strips. The abutment and alignment of these screen panel edge strips has been somewhat difficult to obtain in the field. This has increased the time that is required to both initially install the prior systems and to then replace worn screen panels with replacement screen panels. When a machine, which is operating in an industrial setting, must be taken out of service for repair or replacement of essential elements, that is a loss of that machine's production capacity. Such losses need to be kept at a minimum.
Several of the prior screen panel securement arrangements have required numerous parts and have been expensive to make and install. As discussed above, when a production machine is taken out of service, money is lost. It is thus imperative that the screen panel retainer system be relatively simple, having a limited number of components, that it be quick and easy in its installation, and universal in its ability to adapt to all of the various vibrating separatory machines that are used in the industry. Various machines utilize deck stringer tubes that are secured atop machine cross frame tubes which are frame components of the vibrating separatory machines. The deck stringer tubes are typically 2″×2″ hollow steel tubes and are provided with mounting holes spaced along an upper surface of each such deck stringer tube at a spacing distance of 4″. Other machines are provided with angle iron members that are secured to the cross members of the vibrating separatory machine. The screen panel retainer system must be adaptable for use with the diverse separatory machines that are currently in use.
A vibrating separatory machine uses an array of screen panels to separate solid materials from a slurry. The screen panels are situated in an array that typically utilizes a plurality of screens abutting each other, or adjacent to each other both in a direction of material flow and also in a direction that is traverse to the material flow direction. It is the exposed surface area of these screen panels which accomplishes the material separation. The greater the amount of exposed screen surface, the greater capacity for material separation the machine will have. In some of the prior systems, both those made by the assignee of the subject application, and by others, the retainer structures have tended to cover over substantial portions of the sides or edges of adjacent ones of the screen panels. While that reduction in available screen surface area may amount to only 5% of the total screen surface area, that is still 5% of the total screen surface area which is no longer available for accomplishing the machine's primary objective of separation of solids from a slurry. Any increase in open screen area will improve the operating characteristics of the vibrating separatory machine that uses the screen panel center retainer system of the present invention.
It will thus be understood that a need exists for a screen panel retainer system which overcomes the limitations of the prior systems, which is easily installed and operable, which is adaptable to various deck stringer tubes and machine frame machine cross frame tubes and which does not obstruct open screen area. The screen panel retainer system, in accordance with the present invention, overcomes the limitations of prior art and is a substantial advantage over the presently available systems.